This is the third installment of my “book report” on “The Uninhabitable Earth” by David Wallace-Wells. I would encourage you to read it and share it, but if you aren’t able to read the book, let’s talk about it’s ideas here.
Hunger. It’s more personal than heat. Everyone knows what it feels like to be hungry. Too many know what it feels like to starve. And things aren’t really that bad at the moment. If we continue on our business-as-usual trajectory though, hunger for most of us will become a major issue.
Food is basically energy. Plants capture sunlight and convert it, along with CO2 and water into biomass and sugars. Animals consume plants. Humans consume plants and animals.
There is only so much edible plant mass that can be grown. The same is true for animal protein. And, over the thousands of years of human civilization, the areas suited to plant growth have been discovered and exploited. Civilization began in the “fertile crescent” in what is now the Middle East.
Other valuable farmland appeared in areas where river deltas and valleys provided nutrient rich soil. Crops grew well in these areas and humans were able to establish villages and cities once they began to cultivate agriculture. Soil is not infinite, and we are using it up/allowing it to erode and are losing billions of tons of it a year. (Last year 75 billions tons of soil were lost).
Industrial farming practices such as tilling and use of agrochemicals, as well as deforestation to produce farmland have dramatically increased the rate of soil erosion. Around the world, topsoil is vanishing much faster than it forms. According to David Montgomery, a geologist at the University of Washington, its clear that we're losing more and more topsoil every day. "The estimate is that we are now losing about 1 percent of our topsoil every year to erosion, most of this caused by agriculture." The United States is losing soil at a rate 10 times faster than the soil replenishment rate while China and India are losing soil 30 to 40 times faster. With soil erosion rates so much higher than the replenishment rate, it is no wonder that the world is quickly running out of fertile topsoil. Table 1 shows the severity of topsoil degradation worldwide.
Continent |
Total Area |
Degraded Area |
% Degraded |
Africa |
14.236 |
10.458 |
73 |
Asia |
18.814 |
13.417 |
71 |
Australia |
7.012 |
3.759 |
54 |
Europe |
1.465 |
0.943 |
65 |
North America |
5.782 |
4.286 |
74 |
South America |
4.207 |
3.058 |
73 |
Total |
51.597 |
35.922 |
70 |
|
Table 1: Estimates of all degraded lands (in million km2) in dry areas. |
large.stanford.edu/...
In addition to the problem of losing soil because of the above reasons, we are slowly losing areas where crops can grow because of climate change. The weather is getting too warm for certain crops to flourish, and it is only going to get worse. According to Wallace-Wells, the basic rule of thumb for heat and cereal crops, is the for every degree Celsius of warming, the crop yield will decrease by 10%. We are at approximately 1.1 degree Celsius of warming so far. As the climate warms, areas where we are growing crops right now will become unsuitable, and areas where it was once too cold for crops will open up. The problem is, the areas where we currently grow crops already have the ideal temperature suited to grow them. And the lands that are becoming warmer don’t have soils best suited to producing our current crops. The belt of land across the globe with temperatures best suited to growing wheat is moving poleward by 160 miles a decade. Thus, we are losing crop land to climate change as well.
As the climate warms, arable land is becoming desert. At 2.5 degrees Celsius of warming, the world could enter a global food deficit. The world simply could not produce enough calories to feed all of us. By 2080, without drastic emissions reductions, Southern Europe could be in “permanent extreme drought” worse than the “Dust Bowl” of the 1930s. The same goes for Iraq, Syria, most of the Middle East, the densely populated areas of Australia, South America, and Africa, and the ‘bread basket’ region of China.
If warming hits 4 degrees Celsius, the US corn yield is expected to be halved. The next three biggest producers, Brazil, China, and Argentina would be expected to lose 20% of their yields.
It’s not just the heat though, as the climate warms and moistens, fungus and diseases creep further northward into plants not suited to resisting them. Insect activity and weed growth increases, further threatening crop yields or encouraging more pesticide use. Flooding ruins viable crop land for a growing season. Saltwater intrusion can make soils too salty to produce crops.
If human populations continues to grow as expected, we are going to need twice as much food by 2050. In the West, we have enjoyed the bounty of being the first cultures to achieve modernity and all of its benefits. Now, as what was once known as the “third world” advances hundreds of millions of their citizens into the middle class, their tastes are expanding. China and India are going to seek diets higher in animal protein than they have known before. Greenpeace estimates that the world would need to cut it meat and dairy consumption in half by 2050 in order to avoid dangerous climate change. That would be a tough sale to the West, but think about the hundreds of millions of people emerging into the middle class being told that they can’t enjoy what Western nations have had for decades.
Interestingly, as CO2 makes plants grow faster, but it also makes them less nutrient dense. Vitamins and nutrients in our crops have been decreasing since 1950 by 1/3. The CO2 does increase the sugars in the plants though, so our crops are becoming more and more like “junk food”. (It makes me want to smack those ignorant, bad faith, conservatives who talk about CO2 being great for plants.) For millions of the world’s poor who rely upon plants for their protein, this decrease in plant nutrients could become catastrophic.
It would be nice to have more magic bullets in the form of crops genetically modified to be more sol tolerant and heat/flood/drought resistant. But we will probably need a combination of that as well as decreasing global consumption of animal proteins and drastically decreasing our emissions. Individual choices are important, but not anywhere near as effective as national policies and regulations.
*I know this stuff is a slog, but if you are still with me, thanks for reading. This is important.
We are only about 20% of the way through The Uninhabitable Earth. More to come.
Peace,
BL Hokie